On Sunday, the United States called for regional leaders to work to cut funding and recruitment for two jihadist groups -- the Islamic State of Iraq and the Levant and Al-Nusra Front -- saying foreign fighters were going to Syria and then carrying out attacks in Iraq.

ISIL operates in both Syria and Iraq, while Al-Nusra Front is based in Syria but has also been linked to Iraq.

Washington called for "active measures to police the funding and recruitment" of the groups.

On Sunday, Prime Minister Nuri al-Maliki said a Sunni Arab anti-government protest camp in Anbar has become a "headquarters for the leadership of Al-Qaeda," calling on legitimate protesters to leave before security forces move in.

Violence in the country has reached a level not seen since 2008, when the country was emerging from a period of brutal sectarian killings.

More than 6,650 people have been killed in Iraq since the beginning of the year, according to AFP figures based on security and medical sources.